Means for controlling combustion



- Jan. 6, 1931.

| w. EGGLESTON MEANS FOR CONTROLLING COMBUSTION Filed July 2 192 4 Sheets-Sheet '1 ii.i..

INVENTOR.

Jan. 6, 1931. w. EGGLESTON 1,738,357

MEANS FOR CONTROLLING COMBUSTION Filed July 2, 1926 4 Shegts-Sheet 2 1 I j 77$ 3/ W if r EH17; 33 my 7/2 77 I @IQ f6 L 3. HZ 7; z; 2% 73 u Z9 Z6 I I I I l lll lll l ivl l g l I I M a? 10 I m m f6 fa Jan. 6, 1931. L. w. EGGLESTON 4 1,738,357

' MEANS FOR CONTROLLING COMBUSTION' Filed July 2, 1926 4 Shee' ts-Sheet 3 IN VENTOR.

INVENTOR.

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Jan. 6, 1931. L. w. EGGLESTON MEANS FOR CONTROLLING COMBUSTION Filed Jfily 2, 1926 4 Sheets-Sheet- 4 Patented .llan. H31

LEWIS W. EGGLESTON, F CLARENCE TOWNSHIP, ERIE COUNTY, NEW YORK, ASSIGINOR TO AMERICAN RADIATOR COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY MEANS FOR GOlN TROLLIN G COMBUSTION Application filed July 2, 1926. Serial No. 120,068.

My invention relates broadly and generally to means for controlling combustion in heating apparatus, and more particularly contemplates the provision of improved means for controlling the supply or flow of fluid fuel to the burner or burners of a fluid fuel-heated apparatus for heating liquids, for example,

water. I

In the preferred embodiment to be herein- 19 after described, the invention is shown as being applied for the control of a gas burner for heating water in heating apparatus commercially designated as boilers for supplying low pressure steam to be supplied to heatradiating elements for house-heating purposes, but I desire it understood that my in vent-ion is not limited to such application,.as

it may with facility and advantage be applied to liquid-heating apparatus for other pur- 2o poses.

The primary object of theinvention is to provide a controlling apparatus which will be comparatively simple in construction and highly efiicient in operation.

The invention consists in the novel and improved construction of apparatus, to be more fully described hereinafter, and the novelty of which will be particularly .pointed out and distinctly claimed.

I have fully and clearly illustrated a preferred embodiment of my invention in the accompanying drawings to be taken as a part of these specifications, and wherein Figure 1 is a view in side elevation of one form of heating apparatus to which my invention is applicable, and showing in elevation my improved controlling means applied thereto. i

Fig. 2 shows in front elevation the heating apparatus shown in Fig. 1, with my invention applied thereto, the latter appearing when looking from the right toward the left of Fig. 1;

Fig. 3 is an enlarged detail view, partly in section, and corresponding to the position shown in Fig. 1; Q

Fig. 4 is a top plan view with a portion broken away, of a liquid level control device to forming one of the elements of my invention;

Fig. 5 is a view in end elevation of the device shown in Fig.4;

Fig. 6 is a sectional view on the line 66 of Fig. 4;

Fig. 7 is a top plan view partly in section, with the parts in dotted lines, of a control valve constituting my invention;

. Fig. 8 is a View in front elevation, partly of reference, 1 designates generally a heating apparatus to which my invention isapplicable, but which specifically is not of my invention, and constitutes no part thereof, except in so far as the same may enter into combination therewith, said heating apparatus being shown merely as an exemplification of one type of apparatus to which my invention is applicable. The heating apparatus disclosed comprises a plurality of hollow sections 2, connected to each other by suitable flow nipples 3 and spaced apart to provide flue spaces 4 which open at their.

lower ends over a space or chamber 5 adapted to receive gaseous fuel burners 6 of any suitable type. The upper ends of the flue spaces 4 open into a hood or dome 7 leading to a draft diverter 8 provided with a suitable draft outlet 9. The burners are provided with forwardly extending air and gas-mixing tubes 10, which are individually con nected by valve connections 11 with a horizontally disposed gas supply manifold 12 connected to a gas supply pipe 13, which may contain a gas pressure control governor 14 of any suitable type. Associated with the main burner is a pilot burner 15 of any suitable type, and connected to a supply pipe 16 which is connected, as at 17 to the main gas supply pipe. The pipe 16 contains a suitable hand-operable valve 16. The features just described do not specifically constitute my invention, and, as stated, are merely disclosed and described in order that my invention will be fully understood.

In the main supply pipe 13 is located a control valve 18, which is adapted to establish and cut oflf the flow of gas to the main burners. This valve is preferably of the snap action type, that is, is provided with a snap mechanism, adapted to snap the valve to either full open or full closed positions, and hold the same in either one of these positions until snapped to the other position. This valve and the snap mechanism is preferably of the construction forming the subject matter of my Letters PatentNo. 1,692,770 granted Nov. 29, 1928. Said valve comprises a casing having end nipples 19 for insertion in said gas-supply pipe, and in said casing is a partition 20 having a' horizontal portion 21 provided with a port 22 surrounded by a valve seat head 23. The upper end of the valve casing is closed by a screw cap or bonnet 24 having an inwardly projecting sleeve 25, the bore of which is concentric with said valve port. Reciprocally mounted in said sleeve is a valve stem 26 carrying at its lower end a valve disk 27 adapted to be seated upon the valve seat 23, and on said stem above said disk is a valve element 28 adapted to engage and seat against the lower end of said sleeve 25 when the valve is moved to full open position. Mounted upon the bonnet is a casing or frame 29 into which the upper end of the valve stem 26 projects. On the upper end of the valve stem is connected a yoke member 30 comprising an intermediate portion 31 secured by a nut 32 on the end of the stem, and including vertical parallel arms 33 provided on" their opposite edges with V- shaped notches 34 constituting seats or fulcrums for the inner ends of oppositely disposed levers 35, the outer endsof which play between spaced abutments 36 on the opposite side members of the-frame 29. The outer ends of the levers are movable to points above and below the points 34 at which they are fulcrum'ed on the yoke member, and; the outer ends of said levers are connected by tension springs 37 to the lower end of a connecting member 38, the upper end of vwhich is pivotally connected at 39 to an operating lever 40. When the operating lever 40 is rocked, the inner ends of the springs 37 may be moved above or below the fulcrums 34 for the levers, whereby the outer ends of the levers 35 are snapped in position against'the upper .or'lower abutments 36 on the frame, and said levers reacton the yoke to snap the valve stem 26 to move the valve disk 27 to full open and-full closed positions.

In so far as this valve and its movements as so far described is fully disclosed in my s'aid Letters Patent No. 1,692,770, it is not necessiary 1to describe the same herein in greater etai On the outer side of one of the yoke members 30 is arranged an outwardly directed bracket member 41, the function of which will appear presently. s

I will now des'cribe'improved means constituting my invention for controlling the functions of this valve 18 in accordance with the condition of the pilot burner flame, said means preferably functioning to permit normal operation of the valve, as will be hereinafter described, so long as the pilot burner flame is burning elficiently to ignite the main burners, but acting in case the pilot burner becomes extinguished, to close said valve and hold it closed so long as that condition exists. On the front wall of the casing Orframe 29 is mounted a supplemental casing 29, in-

so as to be liquid and gas-tight, there being an intervening annular space 49 between said rigid wall and said bellows. .Connected to the lower. end or head of the rigid wall 46 is a tube 50, which opens into said annular space 49, and the opposite end of said tube 15 coiled, as at 51, about a sleeve 52, which surrounds the upper end of the pilot burner 15, said coiled end of the tube 50 being closed and sealed. WVithin said tube is a charge of suitable thermostatic material, for example,

aniline, which boils at approximately 361 F., and when subjected to the heat of the pilot burner flame will exert sufficient force against the bellows 47 to hold the lever 43 upward with the pin 44, out of engagement .with the bracket 41, and thereby permit free normal action of said snap valve, except as hereinafter described. It will be understood that should the pilot burner become extinguished or burn at such a low point as. not to generate sufficient pressure in the thermostatic system to collapse said bellows toward said lever 43, the latter may be moved, by means to be now described, to throw the pin against the bracket 41.

In the supplementary casing 29 and abovesaid lever 43, is arranged means acting normall to urge said lever and the pin 44 towar said bracket. This means preferablycomprises a coiled spring 53 havin'g'one end seated in a spring diskor seat 54 arranged over the lever, and having at its lower end a pointed pin 55 seated in a socket on the upper side of the lever 43, and the upper end of said spring is seated in a spring seat 56 having a square socket 57 to receive a corsive force of said spring is so adjusted that when the pilot flame is burning efliciently the bellows will move the lever against the spring 53 and compress the latter so that the lever 43'and pin 44 will be held up out of engagement with the valve bracket 41, but should the pilot flame burn inefficiently, or become extinguished, the pressure exerted by the bellows will become reduced to a point where the spring will overcome the bellows and move the lever 43 down, throwing the pin 44 against the bracket 41 and thereby moving the valve to closed position, and holding the valve in such position until the pilot I burner is re-ignited or burns sufficiently to collapse the bellows to overcome saidspring. The force of spring 53, under the conditions mentioned, is suflicient to close the valve, irrespective of.v the normal sna mechanism. It is to be noted that the system 1ustdescribed normally permits free movement of the valve disk 27 while the pilot flame is burning, but should the thermostatic system fail to operate to exert suflicient pressure, or become ruptured to permit escape of the thermostatic medium therein, the spring 53 will automatically close the valve. This is an important advantage, because i it is assured that the main valve supply-ing gas to the main burners will be definitely closed, in the event the pilot burner, upon which ignition of the main burners depends, becomes inoperative to ignite said main burners. However, it will be seen that, if desired, the burner can be operated independent of the pilot control, and until such time as a new power element can be provided, or the old one repaired, this being accomplished by raising and holding said lever 43 to a point permitting the snap valve to function normally. U

I will now describe means for controlling said valve by a condition existing within the liquid-containing space of the heater, for example, the temperature of the material being heated, or pressure existing within sai space. In the event pressure within the liquid-containing space is to be empIoyed as the controlling factor, this means preferably comprises a pressure regulator comprising an outer casing connected at its lower end to the steam or pressure space of the boiler above the liquid level therein, for example, by an angle pipe connection 61. Within this casing is an expansible-collapsible bellows 62, the upper edge of which is sealed to the upper edge of said casing and held by the cover 63 of the latter. The lower f end of the bellows is closed by a head 64, and

between the bellows and the casing is pro vided a pressure chamber 65 in communication' through the angle connection with the pressure space of the heating apparatus, so that said bellows will be collapsed when the pressure reaches a determined point. Within the bellows is a plunger 66, the upper end of which cooperateswith a saddle 67 fulcrumed at 68 on a post 69 on the cover 63. Extending through said saddle is a lever 70, one end of said lever being connected by a link or connecting rod 71 to the lever 40 which operates to snap the snap valve to open or closed positions, under conditions when the pilot control heretofore described functions to permit normal operation of the snap valve. On the opposite end of the lever is a Weight 72 which is adjustable lengthwise thereof, so as to determine the pressure at which said hol lows 62 will be collapsed. So long as the pressure within the boiler is below a certain point, the weight operates to expandthe bellows 62 to permit the end of lever 70 connected to the link 71 to move upward, thereby exerting a pull on said link to swing the valve lever 40 to maintain the valve open and permit supply of gas to themain burner. Should the pressure exceed the point for which the regulator is set, the bellows62 is collapsed by suchpressure, thereby exerting force on the lever 70 to push the link downward and swing the valve lever 40 downward to snap the valve to closed position, cutting oil supply to the burners so long as the pressure exceeds a determined point. It will be understood that this regulator functions under response to the boiler pressure to open and close the valve, unless the latter be held closed by the pilot control heretdfore described, or by a liquid level control to be-hereinafter described. It will alsobe understood that when the pilot control operates to move the valve to closed position, the latter will be held in this position, irrespective of any, operatlon of the pressure-responsive regulator 60a, the connections between the same permitting movement of the regulator but act- 1 ing as a lost-motion connection actuation of the valve. should act at have moved pilot control to prevent such time as the regulator shall the valve to closed position, the

thereby If the pilot control will operate to hold the valve 7 closed, but if the valve should be in open posi tion in response to the 'pressure=responsiveregulator," the pilot control will move the valve to closed position and maintain it in that position. i

I have described above a pressure-responsive device for controlling the sna valve by a condition, i. e, the pressure, existing within the liquid heating apparatus to Which the invention is applied, but it will be understood that in lieu of the pressure-responsive regu- ,la.tor I can with equal facility employ a tem- V perature-responsive device of the same gen- 1 invention for actuating said valve to close the latter, and preferably maintain the same closed when the liquid level in the boiler or heater drops below a certain point. Connected at its upper end, as at 7 2 with the nipple connection 61, is a pipe column 73, the lower end of which is connected, as at 74, to the internal space of the heater, so that said column communicates with the internal space of the heater, above and below the liquid level therein. In the said column is interposed a float chamber 75,.so located as to normally be filled with water when the level in the boiler is at the normal level line, as indicated by the broken line and legend Water level, in Figs. 1 and 2. This float chamber is preferably in the form of a main body 7 5*, consisting, preferably, of an integral casting having upper and lower nipples 7 6 for connection in the column. At one end the main body 7 5 is closed by a neck-like portion 77 secured thereto by suitable bolts 78, and having an upwardly turned outer end 7 9. Within the main body portion is a suitable float 80 rigidly mounted ,on an arm 81 which extends into said neck portion, and is rigidly connected to a dollar 82 (see Fig. 6) on the lower end of a rocking member, preferably in the form of a lever 83 fulcrumed at 84 on ears 85 dependin from a closure cap 86, which is bolted, as at 8 on the outer upper open end of said neck portion, sa1d lever extending upward through an aperture 88 in said cap.

Leakage from the float chamber about said lever 83 is prevented .by means of a cylindrical, expansible-collapsible metallic bellows 89 mounted on and surrounding the lever'83, said bellows being closed by a lower head 90 having a central aperture mounted on the lower end of said lever, said head being held against a shoulder 91 on said lever by means of the collar 82. The collar 82 is held in place on said lever and against the head 90 by a clampingnut 92 threaded on the lower end of the said lever. The upper end of the bellows is secured and sealed to an annular collar or plate 93 which projects laterally of the bellows and'is clamped by the cover plate 86 against an internal shoulder 94 on the outer open end of said neck portion 79. It

will be seen that the bellows efiectually seals the casing about the lever 83, and when the latter is oseillatd or rocked, 'said bellows will yield or flex laterally. On the cover plate 86 are provided ears or walls 95 connected by a cross-wall 96 and in which are rotatably mounted the opposite ends of a horizontal shaft 97, one end of which projects at 98 beyond the side face of said neck, as shown in Figs. 4 and 5, and has loosely mounted thereon a crank arm 99, comprising a U-shaped member, the arms 100, 101 of which are provided with apertures to receive loosely the projecting end 98 of the shaft 97, and one of which arms 101 is made longer than the other and provided with a laterally extending pin 102. The arms of said crank are connected by a cross-pin 103, for a purpose to be presently described.

On the shaft 97 between the ears or walls 95 is a radial pin 104, which is adapted to be engaged by an adjustablescrew pin 105 held by the upper end of said oscillating lever 83, the arrangement being such that when the float descends, due to a suflicient drop of liquid level, the oscillating lever will be rocked to cause pin 105 to engage said pin 104 and rotate the shaft 97 counter-clockwise of Fig. 6. The pin 105 is threaded in the lever 83 and adjustably held in place by a lock nut 106. Also on the said shaft 97 and located between the arms 100, 101 of the crank is a laterally projecting pin 107 adapted to cooperate with the transverse pin 103 connecting said arms. The pins 104, 107 on the shaft are arranged at an angle to each other (see l ig. 6), so determined that when the float 80 is elevated above the controlling level in the boiler, said oscillating lever 83 will permit the pin 104 to be moved manually into engagement with pin 105, and the pin 107 will be moved so that the crank may be manually operated to an overcenter position "with the transverse pin 103 in engagement.therewith. Connected pivotally to the pin 102 on the outer end of the crank arm 101, is a link 108, to which is secured a suspension connection, preferably a chain 109, which suspends a weight 110, and carrying a plunger pin 111 working in a sleeve 112 connected to the up- 'per portion of the casing 29 of the snap valve,

said pin 111 beinglocated over the bracket 41 heretofore described. The arrangement is such that when there is a proper liquid level in the boiler the float will be raised so as to swing the oscillating lever 83 to the position shown in Fig. 6, in which the pin 104 may be adjusted to engage the adjustment screw 105, and the crank raised and held in an overcenter posit-ion to suspend the weight, said crank being held in this position by engagement of the transverse pin 103 with the pin 107 on the shaft 97. With the parts in this position, the weight and plunger are elevated, and if the pilot burner is working, the snap valve is free to be controlled by the pressure or temperature-responsive regulator. Should the water level Lvaaaev .moving the plunger 111 into engagement with bracket 41 and closing the valve, or if the same already be closed under control of the pressure-responsive regulator, or the pilot burner control, will operate to hold it closed. When the float mechanism has operated to close the main valve, the latter will be held closed against any operation by either the pilot burner control or the pressure regulator control, and no gas can pass to the main burner 6 until the float mechanism is reset manually, which would be done normally after an attendant had supplied enough water to the boiler to bring the level been to a point to raise the float to safety position. When the float mechanism is to be reset, the attendant rotates the crank in a clockwise direction, throwing the transverse pin 103 against the pin 107 on the shaft 97, and in turn rotating the latter until the upper end of the crank which suspends the chain moves over center and the pin 104 is brought against the adjustment screw 105 on the upper end of oscillating lever 83.

From the above description it will be ap parent that I have provided efficient means which will assure proper operation of a liquid heating apparatus. It assures that the main gas burner supply will be distinctlycut ofi Whenever the pilot burner is not in condition to ignite the main burners when the gas is turned on to the latter by means of the automatic, thermostatic or pressure regulat-or, subject to heat conditions in the liquid space of the heater, and provides for automatic resumption of the thermostatic or pressure regulator control when the attendant has seento it that the pilot burner contrpl is functioning properly, or that the pilot burner is ignited. It also assures that irrespective of the functioning of the thermostatic or pressure regulator control and the pilot burner control, or either of them, a fall of liquid level below the danger point will positively close and maintain closed the main gas supply valve, and the vboiler cannot function until the water supply is replenished and the liquid level control is reset manually. Furthermore, the particular construction of the liquid level control adords an eficient manual I device for closing ed the main valve when desired, ,as all it is necessaryfor an attendant to'do is-to swing the crank from its overcenter set position to permit the weight to descend and hold the valve, thus dispensing with additional valve control, manual or otherwise,

in addition to the main snap valve control.

By the term heat condition as employed opening of said valve by said herein and in the appended claims, I mean either an increase or decrease of sensible heat as indicated by temperature in the liquidcontaining space or temperature of the liquid, or an increase or'd'ecrease of fluid pressure in the liquid-containing space resulting from increase or decrease of sensible heat-or other causetherein.

What I claim and desire to secure by Letters Patent of the United States is 1. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner for heating said apparatus, a valve controlling supply of fuel to said burner, a pilot burner, means responsive to a heat condition in said liquidcontaining space to open and close said valve, means for automatically closing said valve when the pilot burner flame is extinguished, and means responsive to a variation of liquid level in said space for closing said valve in opposition to opening of said valve by said first-named means.

2. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner for heating said apparatus, a valve controlling supply of fuel to said burner, a pilot burner, means responsive to a heat condition in said liquid-containing space to open and close said valve, means for automatically closing said valve when the pilot burner flame is extinguished, and means responsive to a variation of liquid level in said space and operative to'close said valve and render inefiective operation of said firstnamed means to open said valve when said second-named means is in position to permit operation of said valve by said first-named means.

3. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner for heating said apparatus, a valve controlling supply of fuel to saidburner, a pilot burner, means responsive to a pressure in said liquid-containing space to open and close said valve, means for automatically closing said valve when the pilot burner flame is extinguished, and means responsive to a variation of liquid level in said space for closing said valve in opposition to opening of said valve by said first-named means.

4. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner to heat said apparatus, a valve controlling supply/of fuel to said burner, means,.res'ponsive to a heat condition in said liquid-containing space to open and close said valve, means acting by gravity to close said'valve, and means responsive to a variation of liquid level in said containing space to release said last-named means to close said valve in op osition to rst-named means.

5. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner to heat said apparatus, a valve controlling supply of fuel to said burner, means responsive to a heat condition in said liquid-containing space to open and close said valve, means acting by gravity to close said valve, holding means for holding said last-named means in position to permit operation of the valve by said firstnamed means, and means responsive to a variation of liquid level in said liquid-containing space torelease said holding means to permit said gravity-acting means to close said valve in oppositionto operation of said first-named means acting to open said valve.

6. In combination, a heating apparatus having a liquid-containing space for liquid to be-heated, a fluid fuel burner toheat said apparatus, a valve controlling supply of fuel to said burner, means responsive to a heat condition in said liquid-containing space to open and close said valve, means acting by gravity to close said valve, holding means for bolding said last-named means in position to permit operation of the valve by said first-named means, and a float responsive to a variation of liquid level in said liquid-containing space to release said holding means'to permit said gravity-acting means to close said valve in opposition to operation of said first-named means acting to open said valve.

- 7. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner to heat said apparatus, a valve controlling supply of fuel to said burner, means responsive to a heat a condition in said liquid-containing space to open and close said valve, means acting by gravity to close said valve, an over-center device acting when in one position to hold said gravity means whereby the valve is free to operate under the control of said first-named means and. when in another position to release said gravity means to close said valve, and means responsive to a variation of liquid level in said liquid-containing space to move said over-center device to the position to release said gravity means to close said valve in opposition to operation of said first-named means acting to open said valve.

j- 8. In combination, a heating apparatus having a liquid-containing space for liquid to be heatedfa fluid fuel burner to heat said apparatus, a valve controlling supply of fuel to said burner, means responsive to a heat conoperation of said first-named means acting to.

" for operation to be heated, a fluid fuel burner to heat said apparatus, a valve controlling the supply of fuel to said burner, a pilot burner, means responsiveto a heat condition in said liquid containing space to operate said valve, means dependenton substantial failure of the pilot burner flame to close said valve, and operable in response to pilot burner flame to release said valve for operation by said first-named means, and means responsive to a fall of liquid level in said liquid-containing space and operative to close said valve and rend 51' ineffective operation of said first-named means to open said'valve when said secondnamed means is in position to permit operation of said valve by said first-named means.

1 0. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner to heat said apparatus, a valve controlling the supply of fuel to said burner, a pilot burner, means responsive to a heat condition in said liquidcontaining space to operate said valve, means dependent on substantial failure of the pilot burner flame to close said valve and operable in response to pilot burner flame to release said valve for operation by said first-named means, and means responsive to a fall of liquid level in said liquid-containing space and operative to close'said valve and hold the same closed and render inefi'ective operation of said first-named means to open said valve when said second-named means is in -a pilot burner, means responsive to a heat condition in said liquid-containing space to open and close said valve, thermostatic means responsive to said pilot burner flame to close said valve when the pilot burner flame is extin 'uished and to release said valve Imy said first-named means when the pilot burner flame. is burning, and means responsive to a fall of liquid level in said dition in said liquid-containing space to open and close said valve, means acting by gravity liquid-containin space and operative to close automatically said valve and render ineffective operation of said first-named means to open saidvalve when said second-named 7 means is in position to permit operation of said valve by said first-named means.

12. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner for heating said avaaeav apparatus, a snap valve movable to open and closed positions to control supply of fuel to said burner, means responsive to a heat condition in said liquid-containing space to snap said valve open and closed, means tending to close said valve, a plot burner, and thermostatic means acting when the pilot burner flame is burning to opposesaid second-named means and permit free movement of said valve by said first-named means, and acting when the pilot burner flame is extinguished to permit said second-named means to close said valve.

13. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner for heating said apparatus, a snap valve movable to open and closed positions to control supply of fuel to said burner, means responsive to a heat condition in said liquid-containing space to snap said valve open and closed, resilient means tending to close said valve, a pilot burner, and thermostatic means acting when the pilot burner flame is burning to oppose said resilient means and permit free move-,

ment of said valve by said first-named means, and acting when the pilot burner flame is extinguished to permit said resilient means to close said valve.

14. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner for heating said apparatus, a snap valve movable to 0 en and closed positions to control supply of uel to said burner, means responsive to a heat condition in said liquid-containing space to snap said valve open and closed, means tending to close said valve, a pilot burner, thermostatic means acting when the pilot burner flame is burning to oppose said secondnamed means to permit free movement of said valve by said first-named means, and

- actino" when the pilot burner flame is extinguished to permit said second-named means to close said valve, andineans responsive to afall of liquid level in said liquidcontaining space to close said valve and hold itclosed, against operation by said firstnamed means and release of said valve by said thermostatic means.

15. In combination, a heating apparatus having a liquid-containing space for liquid to be heated, a fluid fuel burner for heating said apparatus, a snap valve movable to open and closed positions to control supply of fuel to said burner, means responsive to a heat condition in said liquid-containing space to snap said valve open and closed, resilient means tending toclose said valve, a pilot burner, thermostatic means acting when the pilot burner flame is burning to oppose said resilient means to ermit free movement of said valve by said rst -named means, and acting when the pilot burner flame is extinguished to permit said resilient means to close said valve adapted to valve, and means responsive to a fall of liquid level in said liquid-containing space to close said valve and hold it closed against operation by'said first-named means and release of said valve by said thermostatic means.

16. In combination, a heating apparatus having a liquid-containing space adapted to' said resilient means and permit free operation of the valve by said rst named means, and when thepilot burner flame is extinguished to permit said resilient means to move the lever to close said valve.

17. In combination, a heating apparatus having a liquid-containing space adapted to contain a liquid to be heated, a fluid burner for heating said apparatus, a snap valve adapted to besnapped to open and closed positions to control supply of fuel to said i burner, means responsive to a heat condition in said-liquid-containing space to snap said valve to open and closed positions, a lever cooperating-With said valve, a spring acting on said lever and tending to close said valve,

a pilot burner, a thermostatic'device responsive to a condition ofthe pilot burner flame and acting on said leverwhen the pilot flame is burning to oppose said spring and permit free operation of the valve by said firstnamed means, and when the pilot burner flame is extinguished to permit said spring to move the lever to close said valve, and means responsive to a fall of liquid level in said containingspace to act on said lever to close the valve and maintain it closed against release thereof by said thermostatic means and operation thereof by said first-named means.

18. In an apparatus of the character described, a heating apparatus having a'liquidcontaining space adapted to contain a liquid to be heated, a fluid fuel burner to heat the liquid in said space, a valve controlling supply of fuel to said burner, means acting by gravity to close said valve, holding means for holding said last-named means, and means responsive to a variation of liquid level in said space to release said holding means to permit .said gravity-acting means to close said-valve.

19. In an apparatus of the character described, a heatlng a paratus having a liquidcontaining space a apted to contain a liquid iso to be heated, a fluid fuel burner to heat the liquid in said space, a valve controlling supply of fuel to said burner, means acting by gravity to close said valve, an overcenter device acting when in one position to hold said gravity means, and when in another position to release said gravity means to close said valve, and means responsive to a variation of liquid level in said space to move said overcenter device to the position to release said gravity means to close said valve.

20. In an apparatus of the character described, a heating apparatus having a liquidcontainingspace adapted to contain a liquid to be heated, a fluid fuel burner to heat the.

liquid in said space, a snap valve adapted to be snapped to open and closed positions to control flow of fuel to said burner, a pilot burner, means responsive to a heat characteristic of said apparatus to snap said valve open and closed, a liquid level-responsive de vice to move said valve to closed position in opposition to operation -of said first-named means acting to open said valve, and a thermostatic device acting in response to a rise of temperature of the pilot burner flame to permit said valve to be opened and closed by said first-named means, and acting in response to a fall of temperature of the pilot burner flame to close said-valve.

21. In an apparatus of the character described, a heating apparatus having a liquidcontaining space adapted to contain a liquid to be heated, a fluid fuel burner to heat the liquid in said space, a snap valve adapted to be snapped to open and closed positions to control supply of fluid fuel to said burner, a weighted plunger cooperable with said valve to close the same, means for suspending said plunger to permit the valve to function independently thereof, and means for releasing said plunger to permit the same to gravitate to close said valve.

22. In an apparatus of the character described, a heating apparatus having a liquidcontaining space adapted to contain a liquid to be heated, a fluid fuel burner to heat the liquid in said space, a snap valve adapted to be snapped to, open and closed positions to control supply of fluid fuel to said burner, a weighted plunger cooperable with said valve to close the same, means for suspending said plunger to permit the valve to function independently thereof, and float-responsive means responsive to variation of liquid in said space for releasing said plunger to permit the same to gravitate to close said valve.

23. In an apparatus of the character described, a fluid fuel burner, a snap valve adapted to be snapped to open and closed positions to control flow of fuel to said burner, a pilot burner, a spring normally tending to close said valve, thermostatic means responsive to said pilot burner and acting against said spring and operating upon a drop of pilot burner temperature to permit said scribed, a heating apparatus having a liq-,

uid-contalning space adapted to contain a liquid to be heated, a fluid fuel burner to heat the liquid in said space, a snap valve adapted to be snapped to open and closed positions to control flow of fuel to said burner, a pilot burner, means responsive to a heat condition in the heating apparatus to snap the valve open and closed, a lever cooperating with the valve, a spring acting on said lever and tending to snap the valve closed, thermostatic means responsive to said pilot burner 'and acting on said lever to oppose said spring to permit the valve to be opened and closed and acting upon a drop in pilot burner temperature to permit the spring to close the valve, and a float-controlled device operative upon a variation of liquid level'in said space to close the valve.

25. In an apparatus of the character described, a heating apparatus having a liquidcontaining' space adapted to contain a liquid to be heated, a fluid fuel burner to heat the liquid in said space, a snap valve adapted to be snapped to open and closed positions to control flow of fuel to said burner, a pilot burner, means responsive to a heat condition in the heating apparatus to snap the valve open and closed, a lever cooperating with the valve, a spring acting on said lever and tending to snap the valve closed,'thermostatic means responsive to said pilot burner and acting on said lever to oppose said spring to permit the valve to be opened and closed and acting upon a drop in pilot burner temperature to permit the spring to close the valve, and a v float-released gravity device operative upon a variation of liquid level in said space to close the valve and render ineffective operation .of

ply of fluid fuel to said burner, a gravity acting device cooperable with said valve to close the same, a rocking member, a float for rocking said member in response to a drop in liquid level in said space, a shaft, a crank arm on said shaft, means carried by said arm to support said gravity acting device, and cooperating means between said shaft and rocking member whereby said arm is held in an overcenter position to hold said device susthe same, a. rocking member, a float for rocking said member in response to a drop in liquid level, a shaft, a crank arm on said shaft, a link pivoted on said arm and supporting said gravity acting device, and cooperating means between said shaft and rocking member whereby said arm is held in an overcenter position to hold said device suspended and is moved overcenter by said rocking member to release said device.

28. In an apparatus of the character dej scrlbed, a heating apparatus having a liquiddevice cooperable with said containing space adapted to contain a liquid to be heated, a fluid fuel burner to heat the liquid in said space, a valve to control supply of fluid fuel to said burner, a gravity-acting valve to close the same, a rocking member, a float for rocking said member in response to a drop in liquid level in said space, a shaft, a crank arm pivoted on said shaft,means for limiting movement in one direction of said crank arm relative to said shaft but permitting movement of the crank arm in the opposite direction, means carried, by said arm to support said gravity-acting device, and cooperating means between said shaft and rocking member whereby said, arm is held in an overcenter position to holdsaid device suspended, and

is moved overcenter by said rocking member to release said device.

In testimony whereof I have hereunto signed my name.

. LES W. EGGLESTON. 

